Popup modals are great for replacing the standard window popups that we often fall back on when we want our users to confirm something, or log in, etc.
In this exercise, activate a popup modal that will appear when the user clicks on the 'Open Modal' button and disappears when they click on the 'Close Modal' button inside the popup.
The modal should smoothly fade in and slide up to cover the Open button. The background should darken a little to create a clear distinction between foreground and background, and a little shadow should appear on the buttons when you hover over them.
When you're done, keep this repo handy! Being able to build a custom modal is a great show-off for your future projects.
### Hints
- There's a little Javascript here. Don't worry about it. It's been set up to add/remove the `show` class to the relevant elements when clicked
- Multiple transitions will be required
- Pay close attention to the elements being altered with classes being added or removed
